Wget has to be one of the coolest pieces of software out there. No linux installation should be without it. Today I had to use it to mirror a website that I want to keep a local copy of.

wget -E -H -k -p -nd http://www.website.com/index.html
-E converts the output file to .html if it's not already
-H spans hosts if it's on more than one server
-k converts links to local links
-p gets ALL prerequisites for the page (images,css,javascript,etc)
-nd keeps it from making directories for the output